Skeptics who identify issues with the traditionalist view point to possible anachronisms in The Art of War including terms, Technology (such as anachronistic crossbows and the unmentioned cavalry), philosophical ideas, events, and military techniques that should not have been available to Sun Wu. Additionally, there are no records of professional generals during the Spring and Autumn period; these are only extant from the Warring States period, so there is doubt as to Sun Tzu's rank and generalship. This caused much confusion as to when The Art of War was actually written. The first traditional view is that it was written in 512 BC by the historical Sun Wu, active in the last years of the Spring and Autumn period (c. 722–481 BC). A second view, held by scholars such as Samuel Griffith, places The Art of War during the middle to late Warring States period (c. 481–221 BC). Finally, a third school claims that the slips were published in the last half of the 5th century BC; this is based on how its adherents interpret the bamboo slips discovered at Yin-ch’ueh-shan in 1972 AD.